2 Copyright 1995 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 /* ELF linker code. */
22 static boolean elf_link_add_object_symbols
23 PARAMS ((bfd *, struct bfd_link_info *));
24 static boolean elf_link_add_archive_symbols
25 PARAMS ((bfd *, struct bfd_link_info *));
26 static Elf_Internal_Rela *elf_link_read_relocs
27 PARAMS ((bfd *, asection *, PTR, Elf_Internal_Rela *, boolean));
28 static boolean elf_export_symbol
29 PARAMS ((struct elf_link_hash_entry *, PTR));
30 static boolean elf_adjust_dynamic_symbol
31 PARAMS ((struct elf_link_hash_entry *, PTR));
33 /* This struct is used to pass information to routines called via
34 elf_link_hash_traverse which must return failure. */
36 struct elf_info_failed
39 struct bfd_link_info *info;
42 /* Given an ELF BFD, add symbols to the global hash table as
46 elf_bfd_link_add_symbols (abfd, info)
48 struct bfd_link_info *info;
50 switch (bfd_get_format (abfd))
53 return elf_link_add_object_symbols (abfd, info);
55 return elf_link_add_archive_symbols (abfd, info);
57 bfd_set_error (bfd_error_wrong_format);
62 /* Add symbols from an ELF archive file to the linker hash table. We
63 don't use _bfd_generic_link_add_archive_symbols because of a
64 problem which arises on UnixWare. The UnixWare libc.so is an
65 archive which includes an entry libc.so.1 which defines a bunch of
66 symbols. The libc.so archive also includes a number of other
67 object files, which also define symbols, some of which are the same
68 as those defined in libc.so.1. Correct linking requires that we
69 consider each object file in turn, and include it if it defines any
70 symbols we need. _bfd_generic_link_add_archive_symbols does not do
71 this; it looks through the list of undefined symbols, and includes
72 any object file which defines them. When this algorithm is used on
73 UnixWare, it winds up pulling in libc.so.1 early and defining a
74 bunch of symbols. This means that some of the other objects in the
75 archive are not included in the link, which is incorrect since they
76 precede libc.so.1 in the archive.
78 Fortunately, ELF archive handling is simpler than that done by
79 _bfd_generic_link_add_archive_symbols, which has to allow for a.out
80 oddities. In ELF, if we find a symbol in the archive map, and the
81 symbol is currently undefined, we know that we must pull in that
84 Unfortunately, we do have to make multiple passes over the symbol
85 table until nothing further is resolved. */
88 elf_link_add_archive_symbols (abfd, info)
90 struct bfd_link_info *info;
93 boolean *defined = NULL;
94 boolean *included = NULL;
98 if (! bfd_has_map (abfd))
100 /* An empty archive is a special case. */
101 if (bfd_openr_next_archived_file (abfd, (bfd *) NULL) == NULL)
103 bfd_set_error (bfd_error_no_armap);
107 /* Keep track of all symbols we know to be already defined, and all
108 files we know to be already included. This is to speed up the
109 second and subsequent passes. */
110 c = bfd_ardata (abfd)->symdef_count;
113 defined = (boolean *) bfd_malloc (c * sizeof (boolean));
114 included = (boolean *) bfd_malloc (c * sizeof (boolean));
115 if (defined == (boolean *) NULL || included == (boolean *) NULL)
117 memset (defined, 0, c * sizeof (boolean));
118 memset (included, 0, c * sizeof (boolean));
120 symdefs = bfd_ardata (abfd)->symdefs;
133 symdefend = symdef + c;
134 for (i = 0; symdef < symdefend; symdef++, i++)
136 struct elf_link_hash_entry *h;
138 struct bfd_link_hash_entry *undefs_tail;
141 if (defined[i] || included[i])
143 if (symdef->file_offset == last)
149 h = elf_link_hash_lookup (elf_hash_table (info), symdef->name,
150 false, false, false);
151 if (h == (struct elf_link_hash_entry *) NULL)
153 if (h->root.type != bfd_link_hash_undefined)
155 if (h->root.type != bfd_link_hash_undefweak)
160 /* We need to include this archive member. */
162 element = _bfd_get_elt_at_filepos (abfd, symdef->file_offset);
163 if (element == (bfd *) NULL)
166 if (! bfd_check_format (element, bfd_object))
169 /* Doublecheck that we have not included this object
170 already--it should be impossible, but there may be
171 something wrong with the archive. */
172 if (element->archive_pass != 0)
174 bfd_set_error (bfd_error_bad_value);
177 element->archive_pass = 1;
179 undefs_tail = info->hash->undefs_tail;
181 if (! (*info->callbacks->add_archive_element) (info, element,
184 if (! elf_link_add_object_symbols (element, info))
187 /* If there are any new undefined symbols, we need to make
188 another pass through the archive in order to see whether
189 they can be defined. FIXME: This isn't perfect, because
190 common symbols wind up on undefs_tail and because an
191 undefined symbol which is defined later on in this pass
192 does not require another pass. This isn't a bug, but it
193 does make the code less efficient than it could be. */
194 if (undefs_tail != info->hash->undefs_tail)
197 /* Look backward to mark all symbols from this object file
198 which we have already seen in this pass. */
202 included[mark] = true;
207 while (symdefs[mark].file_offset == symdef->file_offset);
209 /* We mark subsequent symbols from this object file as we go
210 on through the loop. */
211 last = symdef->file_offset;
222 if (defined != (boolean *) NULL)
224 if (included != (boolean *) NULL)
229 /* Add symbols from an ELF object file to the linker hash table. */
232 elf_link_add_object_symbols (abfd, info)
234 struct bfd_link_info *info;
236 boolean (*add_symbol_hook) PARAMS ((bfd *, struct bfd_link_info *,
237 const Elf_Internal_Sym *,
238 const char **, flagword *,
239 asection **, bfd_vma *));
240 boolean (*check_relocs) PARAMS ((bfd *, struct bfd_link_info *,
241 asection *, const Elf_Internal_Rela *));
243 Elf_Internal_Shdr *hdr;
247 Elf_External_Sym *buf = NULL;
248 struct elf_link_hash_entry **sym_hash;
250 Elf_External_Dyn *dynbuf = NULL;
251 struct elf_link_hash_entry *weaks;
252 Elf_External_Sym *esym;
253 Elf_External_Sym *esymend;
255 add_symbol_hook = get_elf_backend_data (abfd)->elf_add_symbol_hook;
256 collect = get_elf_backend_data (abfd)->collect;
258 /* As a GNU extension, any input sections which are named
259 .gnu.warning.SYMBOL are treated as warning symbols for the given
260 symbol. This differs from .gnu.warning sections, which generate
261 warnings when they are included in an output file. */
266 for (s = abfd->sections; s != NULL; s = s->next)
270 name = bfd_get_section_name (abfd, s);
271 if (strncmp (name, ".gnu.warning.", sizeof ".gnu.warning." - 1) == 0)
276 sz = bfd_section_size (abfd, s);
277 msg = (char *) bfd_alloc (abfd, sz);
281 if (! bfd_get_section_contents (abfd, s, msg, (file_ptr) 0, sz))
284 if (! (_bfd_generic_link_add_one_symbol
286 name + sizeof ".gnu.warning." - 1,
287 BSF_WARNING, s, (bfd_vma) 0, msg, false, collect,
288 (struct bfd_link_hash_entry **) NULL)))
291 if (! info->relocateable)
293 /* Clobber the section size so that the warning does
294 not get copied into the output file. */
301 /* A stripped shared library might only have a dynamic symbol table,
302 not a regular symbol table. In that case we can still go ahead
303 and link using the dynamic symbol table. */
304 if (elf_onesymtab (abfd) == 0
305 && elf_dynsymtab (abfd) != 0)
307 elf_onesymtab (abfd) = elf_dynsymtab (abfd);
308 elf_tdata (abfd)->symtab_hdr = elf_tdata (abfd)->dynsymtab_hdr;
311 hdr = &elf_tdata (abfd)->symtab_hdr;
312 symcount = hdr->sh_size / sizeof (Elf_External_Sym);
314 /* The sh_info field of the symtab header tells us where the
315 external symbols start. We don't care about the local symbols at
317 if (elf_bad_symtab (abfd))
319 extsymcount = symcount;
324 extsymcount = symcount - hdr->sh_info;
325 extsymoff = hdr->sh_info;
328 buf = ((Elf_External_Sym *)
329 bfd_malloc (extsymcount * sizeof (Elf_External_Sym)));
330 if (buf == NULL && extsymcount != 0)
333 /* We store a pointer to the hash table entry for each external
335 sym_hash = ((struct elf_link_hash_entry **)
337 extsymcount * sizeof (struct elf_link_hash_entry *)));
338 if (sym_hash == NULL)
340 elf_sym_hashes (abfd) = sym_hash;
342 if (elf_elfheader (abfd)->e_type != ET_DYN)
346 /* If we are creating a shared library, create all the dynamic
347 sections immediately. We need to attach them to something,
348 so we attach them to this BFD, provided it is the right
349 format. FIXME: If there are no input BFD's of the same
350 format as the output, we can't make a shared library. */
352 && ! elf_hash_table (info)->dynamic_sections_created
353 && abfd->xvec == info->hash->creator)
355 if (! elf_link_create_dynamic_sections (abfd, info))
364 bfd_size_type oldsize;
365 bfd_size_type strindex;
369 /* You can't use -r against a dynamic object. Also, there's no
370 hope of using a dynamic object which does not exactly match
371 the format of the output file. */
372 if (info->relocateable
373 || info->hash->creator != abfd->xvec)
375 bfd_set_error (bfd_error_invalid_operation);
379 /* Find the name to use in a DT_NEEDED entry that refers to this
380 object. If the object has a DT_SONAME entry, we use it.
381 Otherwise, if the generic linker stuck something in
382 elf_dt_needed_name, we use that. Otherwise, we just use the
383 file name. If the generic linker put a null string into
384 elf_dt_needed_name, we don't make a DT_NEEDED entry at all,
385 even if there is a DT_SONAME entry. */
387 name = bfd_get_filename (abfd);
388 if (elf_dt_needed_name (abfd) != NULL)
390 name = elf_dt_needed_name (abfd);
394 s = bfd_get_section_by_name (abfd, ".dynamic");
397 Elf_External_Dyn *extdyn;
398 Elf_External_Dyn *extdynend;
402 dynbuf = (Elf_External_Dyn *) bfd_malloc ((size_t) s->_raw_size);
406 if (! bfd_get_section_contents (abfd, s, (PTR) dynbuf,
407 (file_ptr) 0, s->_raw_size))
410 elfsec = _bfd_elf_section_from_bfd_section (abfd, s);
413 link = elf_elfsections (abfd)[elfsec]->sh_link;
416 extdynend = extdyn + s->_raw_size / sizeof (Elf_External_Dyn);
417 for (; extdyn < extdynend; extdyn++)
419 Elf_Internal_Dyn dyn;
421 elf_swap_dyn_in (abfd, extdyn, &dyn);
422 if (add_needed && dyn.d_tag == DT_SONAME)
424 name = bfd_elf_string_from_elf_section (abfd, link,
429 if (dyn.d_tag == DT_NEEDED)
431 struct bfd_link_needed_list *n, **pn;
434 n = ((struct bfd_link_needed_list *)
435 bfd_alloc (abfd, sizeof (struct bfd_link_needed_list)));
436 fnm = bfd_elf_string_from_elf_section (abfd, link,
438 if (n == NULL || fnm == NULL)
440 anm = bfd_alloc (abfd, strlen (fnm) + 1);
447 for (pn = &elf_hash_table (info)->needed;
459 /* We do not want to include any of the sections in a dynamic
460 object in the output file. We hack by simply clobbering the
461 list of sections in the BFD. This could be handled more
462 cleanly by, say, a new section flag; the existing
463 SEC_NEVER_LOAD flag is not the one we want, because that one
464 still implies that the section takes up space in the output
466 abfd->sections = NULL;
468 /* If this is the first dynamic object found in the link, create
469 the special sections required for dynamic linking. */
470 if (! elf_hash_table (info)->dynamic_sections_created)
472 if (! elf_link_create_dynamic_sections (abfd, info))
478 /* Add a DT_NEEDED entry for this dynamic object. */
479 oldsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
480 strindex = _bfd_stringtab_add (elf_hash_table (info)->dynstr, name,
482 if (strindex == (bfd_size_type) -1)
485 if (oldsize == _bfd_stringtab_size (elf_hash_table (info)->dynstr))
488 Elf_External_Dyn *dyncon, *dynconend;
490 /* The hash table size did not change, which means that
491 the dynamic object name was already entered. If we
492 have already included this dynamic object in the
493 link, just ignore it. There is no reason to include
494 a particular dynamic object more than once. */
495 sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj,
497 BFD_ASSERT (sdyn != NULL);
499 dyncon = (Elf_External_Dyn *) sdyn->contents;
500 dynconend = (Elf_External_Dyn *) (sdyn->contents +
502 for (; dyncon < dynconend; dyncon++)
504 Elf_Internal_Dyn dyn;
506 elf_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon,
508 if (dyn.d_tag == DT_NEEDED
509 && dyn.d_un.d_val == strindex)
518 if (! elf_add_dynamic_entry (info, DT_NEEDED, strindex))
524 hdr->sh_offset + extsymoff * sizeof (Elf_External_Sym),
526 || (bfd_read ((PTR) buf, sizeof (Elf_External_Sym), extsymcount, abfd)
527 != extsymcount * sizeof (Elf_External_Sym)))
532 esymend = buf + extsymcount;
533 for (esym = buf; esym < esymend; esym++, sym_hash++)
535 Elf_Internal_Sym sym;
541 struct elf_link_hash_entry *h;
543 boolean size_change_ok, type_change_ok;
546 elf_swap_symbol_in (abfd, esym, &sym);
548 flags = BSF_NO_FLAGS;
550 value = sym.st_value;
553 bind = ELF_ST_BIND (sym.st_info);
554 if (bind == STB_LOCAL)
556 /* This should be impossible, since ELF requires that all
557 global symbols follow all local symbols, and that sh_info
558 point to the first global symbol. Unfortunatealy, Irix 5
562 else if (bind == STB_GLOBAL)
564 if (sym.st_shndx != SHN_UNDEF
565 && sym.st_shndx != SHN_COMMON)
570 else if (bind == STB_WEAK)
574 /* Leave it up to the processor backend. */
577 if (sym.st_shndx == SHN_UNDEF)
578 sec = bfd_und_section_ptr;
579 else if (sym.st_shndx > 0 && sym.st_shndx < SHN_LORESERVE)
581 sec = section_from_elf_index (abfd, sym.st_shndx);
585 sec = bfd_abs_section_ptr;
587 else if (sym.st_shndx == SHN_ABS)
588 sec = bfd_abs_section_ptr;
589 else if (sym.st_shndx == SHN_COMMON)
591 sec = bfd_com_section_ptr;
592 /* What ELF calls the size we call the value. What ELF
593 calls the value we call the alignment. */
598 /* Leave it up to the processor backend. */
601 name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, sym.st_name);
602 if (name == (const char *) NULL)
607 if (! (*add_symbol_hook) (abfd, info, &sym, &name, &flags, &sec,
611 /* The hook function sets the name to NULL if this symbol
612 should be skipped for some reason. */
613 if (name == (const char *) NULL)
617 /* Sanity check that all possibilities were handled. */
618 if (sec == (asection *) NULL)
620 bfd_set_error (bfd_error_bad_value);
624 if (bfd_is_und_section (sec)
625 || bfd_is_com_section (sec))
630 size_change_ok = false;
631 type_change_ok = false;
632 if (info->hash->creator->flavour == bfd_target_elf_flavour)
634 /* We need to look up the symbol now in order to get some of
635 the dynamic object handling right. We pass the hash
636 table entry in to _bfd_generic_link_add_one_symbol so
637 that it does not have to look it up again. */
638 h = elf_link_hash_lookup (elf_hash_table (info), name,
644 while (h->root.type == bfd_link_hash_indirect
645 || h->root.type == bfd_link_hash_warning)
646 h = (struct elf_link_hash_entry *) h->root.u.i.link;
648 /* It's OK to change the type if it used to be a weak
650 type_change_ok = (h->root.type == bfd_link_hash_defweak
651 || h->root.type == bfd_link_hash_undefweak);
653 /* It's OK to change the size if it used to be a weak
654 definition, or if it used to be undefined, or if we will
655 be overriding an old definition.
657 size_change_ok = (type_change_ok
658 || h->root.type == bfd_link_hash_undefined);
660 /* If we are looking at a dynamic object, and this is a
661 definition, we need to see if it has already been defined
662 by some other object. If it has, we want to use the
663 existing definition, and we do not want to report a
664 multiple symbol definition error; we do this by
665 clobbering sec to be bfd_und_section_ptr. */
666 if (dynamic && definition)
668 if (h->root.type == bfd_link_hash_defined
669 || h->root.type == bfd_link_hash_defweak
670 || (h->root.type == bfd_link_hash_common
671 && bind == STB_WEAK))
673 sec = bfd_und_section_ptr;
675 size_change_ok = true;
679 /* Similarly, if we are not looking at a dynamic object, and
680 we have a definition, we want to override any definition
681 we may have from a dynamic object. Symbols from regular
682 files always take precedence over symbols from dynamic
683 objects, even if they are defined after the dynamic
684 object in the link. */
687 && (h->root.type == bfd_link_hash_defined
688 || h->root.type == bfd_link_hash_defweak)
689 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
690 && (bfd_get_flavour (h->root.u.def.section->owner)
691 == bfd_target_elf_flavour)
692 && (elf_elfheader (h->root.u.def.section->owner)->e_type
695 /* Change the hash table entry to undefined, and let
696 _bfd_generic_link_add_one_symbol do the right thing
697 with the new definition. */
698 h->root.type = bfd_link_hash_undefined;
699 h->root.u.undef.abfd = h->root.u.def.section->owner;
700 size_change_ok = true;
704 if (! (_bfd_generic_link_add_one_symbol
705 (info, abfd, name, flags, sec, value, (const char *) NULL,
706 false, collect, (struct bfd_link_hash_entry **) sym_hash)))
710 while (h->root.type == bfd_link_hash_indirect
711 || h->root.type == bfd_link_hash_warning)
712 h = (struct elf_link_hash_entry *) h->root.u.i.link;
718 && (flags & BSF_WEAK) != 0
719 && ELF_ST_TYPE (sym.st_info) != STT_FUNC
720 && info->hash->creator->flavour == bfd_target_elf_flavour
721 && h->weakdef == NULL)
723 /* Keep a list of all weak defined non function symbols from
724 a dynamic object, using the weakdef field. Later in this
725 function we will set the weakdef field to the correct
726 value. We only put non-function symbols from dynamic
727 objects on this list, because that happens to be the only
728 time we need to know the normal symbol corresponding to a
729 weak symbol, and the information is time consuming to
730 figure out. If the weakdef field is not already NULL,
731 then this symbol was already defined by some previous
732 dynamic object, and we will be using that previous
733 definition anyhow. */
740 /* Get the alignment of a common symbol. */
741 if (sym.st_shndx == SHN_COMMON
742 && h->root.type == bfd_link_hash_common)
743 h->root.u.c.p->alignment_power = bfd_log2 (sym.st_value);
745 if (info->hash->creator->flavour == bfd_target_elf_flavour)
751 /* Remember the symbol size and type. */
753 && (definition || h->size == 0))
755 if (h->size != 0 && h->size != sym.st_size && ! size_change_ok)
756 (*_bfd_error_handler)
757 ("Warning: size of symbol `%s' changed from %lu to %lu in %s",
758 name, (unsigned long) h->size, (unsigned long) sym.st_size,
759 bfd_get_filename (abfd));
761 h->size = sym.st_size;
763 if (ELF_ST_TYPE (sym.st_info) != STT_NOTYPE
764 && (definition || h->type == STT_NOTYPE))
766 if (h->type != STT_NOTYPE
767 && h->type != ELF_ST_TYPE (sym.st_info)
769 (*_bfd_error_handler)
770 ("Warning: type of symbol `%s' changed from %d to %d in %s",
771 name, h->type, ELF_ST_TYPE (sym.st_info),
772 bfd_get_filename (abfd));
774 h->type = ELF_ST_TYPE (sym.st_info);
777 /* Set a flag in the hash table entry indicating the type of
778 reference or definition we just found. Keep a count of
779 the number of dynamic symbols we find. A dynamic symbol
780 is one which is referenced or defined by both a regular
781 object and a shared object, or one which is referenced or
782 defined by more than one shared object. */
783 old_flags = h->elf_link_hash_flags;
788 new_flag = ELF_LINK_HASH_REF_REGULAR;
790 new_flag = ELF_LINK_HASH_DEF_REGULAR;
792 || (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
793 | ELF_LINK_HASH_REF_DYNAMIC)) != 0)
799 new_flag = ELF_LINK_HASH_REF_DYNAMIC;
801 new_flag = ELF_LINK_HASH_DEF_DYNAMIC;
802 if ((old_flags & new_flag) != 0
803 || (old_flags & (ELF_LINK_HASH_DEF_REGULAR
804 | ELF_LINK_HASH_REF_REGULAR)) != 0
805 || (h->weakdef != NULL
806 && (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
807 | ELF_LINK_HASH_REF_DYNAMIC)) != 0))
811 h->elf_link_hash_flags |= new_flag;
812 if (dynsym && h->dynindx == -1)
814 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
816 if (h->weakdef != NULL
818 && h->weakdef->dynindx == -1)
820 if (! _bfd_elf_link_record_dynamic_symbol (info,
828 /* Now set the weakdefs field correctly for all the weak defined
829 symbols we found. The only way to do this is to search all the
830 symbols. Since we only need the information for non functions in
831 dynamic objects, that's the only time we actually put anything on
832 the list WEAKS. We need this information so that if a regular
833 object refers to a symbol defined weakly in a dynamic object, the
834 real symbol in the dynamic object is also put in the dynamic
835 symbols; we also must arrange for both symbols to point to the
836 same memory location. We could handle the general case of symbol
837 aliasing, but a general symbol alias can only be generated in
838 assembler code, handling it correctly would be very time
839 consuming, and other ELF linkers don't handle general aliasing
841 while (weaks != NULL)
843 struct elf_link_hash_entry *hlook;
846 struct elf_link_hash_entry **hpp;
847 struct elf_link_hash_entry **hppend;
850 weaks = hlook->weakdef;
851 hlook->weakdef = NULL;
853 BFD_ASSERT (hlook->root.type == bfd_link_hash_defined
854 || hlook->root.type == bfd_link_hash_defweak
855 || hlook->root.type == bfd_link_hash_common
856 || hlook->root.type == bfd_link_hash_indirect);
857 slook = hlook->root.u.def.section;
858 vlook = hlook->root.u.def.value;
860 hpp = elf_sym_hashes (abfd);
861 hppend = hpp + extsymcount;
862 for (; hpp < hppend; hpp++)
864 struct elf_link_hash_entry *h;
867 if (h != NULL && h != hlook
868 && (h->root.type == bfd_link_hash_defined
869 || h->root.type == bfd_link_hash_defweak)
870 && h->root.u.def.section == slook
871 && h->root.u.def.value == vlook)
875 /* If the weak definition is in the list of dynamic
876 symbols, make sure the real definition is put there
878 if (hlook->dynindx != -1
881 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
896 /* If this object is the same format as the output object, and it is
897 not a shared library, then let the backend look through the
900 This is required to build global offset table entries and to
901 arrange for dynamic relocs. It is not required for the
902 particular common case of linking non PIC code, even when linking
903 against shared libraries, but unfortunately there is no way of
904 knowing whether an object file has been compiled PIC or not.
905 Looking through the relocs is not particularly time consuming.
906 The problem is that we must either (1) keep the relocs in memory,
907 which causes the linker to require additional runtime memory or
908 (2) read the relocs twice from the input file, which wastes time.
909 This would be a good case for using mmap.
911 I have no idea how to handle linking PIC code into a file of a
912 different format. It probably can't be done. */
913 check_relocs = get_elf_backend_data (abfd)->check_relocs;
915 && abfd->xvec == info->hash->creator
916 && check_relocs != NULL)
920 for (o = abfd->sections; o != NULL; o = o->next)
922 Elf_Internal_Rela *internal_relocs;
925 if ((o->flags & SEC_RELOC) == 0
926 || o->reloc_count == 0)
929 /* I believe we can ignore the relocs for any section which
930 does not form part of the final process image, such as a
931 debugging section. */
932 if ((o->flags & SEC_ALLOC) == 0)
935 internal_relocs = elf_link_read_relocs (abfd, o, (PTR) NULL,
936 (Elf_Internal_Rela *) NULL,
938 if (internal_relocs == NULL)
941 ok = (*check_relocs) (abfd, info, o, internal_relocs);
943 if (! info->keep_memory)
944 free (internal_relocs);
961 /* Create some sections which will be filled in with dynamic linking
962 information. ABFD is an input file which requires dynamic sections
963 to be created. The dynamic sections take up virtual memory space
964 when the final executable is run, so we need to create them before
965 addresses are assigned to the output sections. We work out the
966 actual contents and size of these sections later. */
969 elf_link_create_dynamic_sections (abfd, info)
971 struct bfd_link_info *info;
974 register asection *s;
975 struct elf_link_hash_entry *h;
976 struct elf_backend_data *bed;
978 if (elf_hash_table (info)->dynamic_sections_created)
981 /* Make sure that all dynamic sections use the same input BFD. */
982 if (elf_hash_table (info)->dynobj == NULL)
983 elf_hash_table (info)->dynobj = abfd;
985 abfd = elf_hash_table (info)->dynobj;
987 /* Note that we set the SEC_IN_MEMORY flag for all of these
989 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
991 /* A dynamically linked executable has a .interp section, but a
992 shared library does not. */
995 s = bfd_make_section (abfd, ".interp");
997 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1001 s = bfd_make_section (abfd, ".dynsym");
1003 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1004 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1007 s = bfd_make_section (abfd, ".dynstr");
1009 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1012 /* Create a strtab to hold the dynamic symbol names. */
1013 if (elf_hash_table (info)->dynstr == NULL)
1015 elf_hash_table (info)->dynstr = elf_stringtab_init ();
1016 if (elf_hash_table (info)->dynstr == NULL)
1020 s = bfd_make_section (abfd, ".dynamic");
1022 || ! bfd_set_section_flags (abfd, s, flags)
1023 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1026 /* The special symbol _DYNAMIC is always set to the start of the
1027 .dynamic section. This call occurs before we have processed the
1028 symbols for any dynamic object, so we don't have to worry about
1029 overriding a dynamic definition. We could set _DYNAMIC in a
1030 linker script, but we only want to define it if we are, in fact,
1031 creating a .dynamic section. We don't want to define it if there
1032 is no .dynamic section, since on some ELF platforms the start up
1033 code examines it to decide how to initialize the process. */
1035 if (! (_bfd_generic_link_add_one_symbol
1036 (info, abfd, "_DYNAMIC", BSF_GLOBAL, s, (bfd_vma) 0,
1037 (const char *) NULL, false, get_elf_backend_data (abfd)->collect,
1038 (struct bfd_link_hash_entry **) &h)))
1040 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1041 h->type = STT_OBJECT;
1044 && ! _bfd_elf_link_record_dynamic_symbol (info, h))
1047 s = bfd_make_section (abfd, ".hash");
1049 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1050 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1053 /* Let the backend create the rest of the sections. This lets the
1054 backend set the right flags. The backend will normally create
1055 the .got and .plt sections. */
1056 bed = get_elf_backend_data (abfd);
1057 if (! (*bed->elf_backend_create_dynamic_sections) (abfd, info))
1060 elf_hash_table (info)->dynamic_sections_created = true;
1065 /* Add an entry to the .dynamic table. */
1068 elf_add_dynamic_entry (info, tag, val)
1069 struct bfd_link_info *info;
1073 Elf_Internal_Dyn dyn;
1077 bfd_byte *newcontents;
1079 dynobj = elf_hash_table (info)->dynobj;
1081 s = bfd_get_section_by_name (dynobj, ".dynamic");
1082 BFD_ASSERT (s != NULL);
1084 newsize = s->_raw_size + sizeof (Elf_External_Dyn);
1085 newcontents = (bfd_byte *) bfd_realloc (s->contents, newsize);
1086 if (newcontents == NULL)
1090 dyn.d_un.d_val = val;
1091 elf_swap_dyn_out (dynobj, &dyn,
1092 (Elf_External_Dyn *) (newcontents + s->_raw_size));
1094 s->_raw_size = newsize;
1095 s->contents = newcontents;
1100 /* Read and swap the relocs for a section. They may have been cached.
1101 If the EXTERNAL_RELOCS and INTERNAL_RELOCS arguments are not NULL,
1102 they are used as buffers to read into. They are known to be large
1103 enough. If the INTERNAL_RELOCS relocs argument is NULL, the return
1104 value is allocated using either malloc or bfd_alloc, according to
1105 the KEEP_MEMORY argument. */
1107 static Elf_Internal_Rela *
1108 elf_link_read_relocs (abfd, o, external_relocs, internal_relocs, keep_memory)
1111 PTR external_relocs;
1112 Elf_Internal_Rela *internal_relocs;
1113 boolean keep_memory;
1115 Elf_Internal_Shdr *rel_hdr;
1117 Elf_Internal_Rela *alloc2 = NULL;
1119 if (elf_section_data (o)->relocs != NULL)
1120 return elf_section_data (o)->relocs;
1122 if (o->reloc_count == 0)
1125 rel_hdr = &elf_section_data (o)->rel_hdr;
1127 if (internal_relocs == NULL)
1131 size = o->reloc_count * sizeof (Elf_Internal_Rela);
1133 internal_relocs = (Elf_Internal_Rela *) bfd_alloc (abfd, size);
1135 internal_relocs = alloc2 = (Elf_Internal_Rela *) bfd_malloc (size);
1136 if (internal_relocs == NULL)
1140 if (external_relocs == NULL)
1142 alloc1 = (PTR) bfd_malloc ((size_t) rel_hdr->sh_size);
1145 external_relocs = alloc1;
1148 if ((bfd_seek (abfd, rel_hdr->sh_offset, SEEK_SET) != 0)
1149 || (bfd_read (external_relocs, 1, rel_hdr->sh_size, abfd)
1150 != rel_hdr->sh_size))
1153 /* Swap in the relocs. For convenience, we always produce an
1154 Elf_Internal_Rela array; if the relocs are Rel, we set the addend
1156 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
1158 Elf_External_Rel *erel;
1159 Elf_External_Rel *erelend;
1160 Elf_Internal_Rela *irela;
1162 erel = (Elf_External_Rel *) external_relocs;
1163 erelend = erel + o->reloc_count;
1164 irela = internal_relocs;
1165 for (; erel < erelend; erel++, irela++)
1167 Elf_Internal_Rel irel;
1169 elf_swap_reloc_in (abfd, erel, &irel);
1170 irela->r_offset = irel.r_offset;
1171 irela->r_info = irel.r_info;
1172 irela->r_addend = 0;
1177 Elf_External_Rela *erela;
1178 Elf_External_Rela *erelaend;
1179 Elf_Internal_Rela *irela;
1181 BFD_ASSERT (rel_hdr->sh_entsize == sizeof (Elf_External_Rela));
1183 erela = (Elf_External_Rela *) external_relocs;
1184 erelaend = erela + o->reloc_count;
1185 irela = internal_relocs;
1186 for (; erela < erelaend; erela++, irela++)
1187 elf_swap_reloca_in (abfd, erela, irela);
1190 /* Cache the results for next time, if we can. */
1192 elf_section_data (o)->relocs = internal_relocs;
1197 /* Don't free alloc2, since if it was allocated we are passing it
1198 back (under the name of internal_relocs). */
1200 return internal_relocs;
1210 /* Record an assignment to a symbol made by a linker script. We need
1211 this in case some dynamic object refers to this symbol. */
1215 NAME(bfd_elf,record_link_assignment) (output_bfd, info, name, provide)
1217 struct bfd_link_info *info;
1221 struct elf_link_hash_entry *h;
1223 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1226 h = elf_link_hash_lookup (elf_hash_table (info), name, true, true, false);
1230 /* If this symbol is being provided by the linker script, and it is
1231 currently defined by a dynamic object, but not by a regular
1232 object, then mark it as undefined so that the generic linker will
1233 force the correct value. */
1235 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
1236 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1237 h->root.type = bfd_link_hash_undefined;
1239 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1240 h->type = STT_OBJECT;
1242 if (((h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC
1243 | ELF_LINK_HASH_REF_DYNAMIC)) != 0
1245 && h->dynindx == -1)
1247 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
1250 /* If this is a weak defined symbol, and we know a corresponding
1251 real symbol from the same dynamic object, make sure the real
1252 symbol is also made into a dynamic symbol. */
1253 if (h->weakdef != NULL
1254 && h->weakdef->dynindx == -1)
1256 if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef))
1264 /* Array used to determine the number of hash table buckets to use
1265 based on the number of symbols there are. If there are fewer than
1266 3 symbols we use 1 bucket, fewer than 17 symbols we use 3 buckets,
1267 fewer than 37 we use 17 buckets, and so forth. We never use more
1268 than 521 buckets. */
1270 static const size_t elf_buckets[] =
1272 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 0
1275 /* Set up the sizes and contents of the ELF dynamic sections. This is
1276 called by the ELF linker emulation before_allocation routine. We
1277 must set the sizes of the sections before the linker sets the
1278 addresses of the various sections. */
1281 NAME(bfd_elf,size_dynamic_sections) (output_bfd, soname, rpath,
1282 export_dynamic, info, sinterpptr)
1286 boolean export_dynamic;
1287 struct bfd_link_info *info;
1288 asection **sinterpptr;
1291 struct elf_backend_data *bed;
1295 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1298 dynobj = elf_hash_table (info)->dynobj;
1300 /* If there were no dynamic objects in the link, there is nothing to
1305 /* If we are supposed to export all symbols into the dynamic symbol
1306 table (this is not the normal case), then do so. */
1309 struct elf_info_failed eif;
1313 elf_link_hash_traverse (elf_hash_table (info), elf_export_symbol,
1319 if (elf_hash_table (info)->dynamic_sections_created)
1321 struct elf_info_failed eif;
1322 struct elf_link_hash_entry *h;
1323 bfd_size_type strsize;
1325 *sinterpptr = bfd_get_section_by_name (dynobj, ".interp");
1326 BFD_ASSERT (*sinterpptr != NULL || info->shared);
1332 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, soname,
1334 if (indx == (bfd_size_type) -1
1335 || ! elf_add_dynamic_entry (info, DT_SONAME, indx))
1341 if (! elf_add_dynamic_entry (info, DT_SYMBOLIC, 0))
1349 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, rpath,
1351 if (indx == (bfd_size_type) -1
1352 || ! elf_add_dynamic_entry (info, DT_RPATH, indx))
1356 /* Find all symbols which were defined in a dynamic object and make
1357 the backend pick a reasonable value for them. */
1360 elf_link_hash_traverse (elf_hash_table (info),
1361 elf_adjust_dynamic_symbol,
1366 /* Add some entries to the .dynamic section. We fill in some of the
1367 values later, in elf_bfd_final_link, but we must add the entries
1368 now so that we know the final size of the .dynamic section. */
1369 h = elf_link_hash_lookup (elf_hash_table (info), "_init", false,
1372 && (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR
1373 | ELF_LINK_HASH_DEF_REGULAR)) != 0)
1375 if (! elf_add_dynamic_entry (info, DT_INIT, 0))
1378 h = elf_link_hash_lookup (elf_hash_table (info), "_fini", false,
1381 && (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR
1382 | ELF_LINK_HASH_DEF_REGULAR)) != 0)
1384 if (! elf_add_dynamic_entry (info, DT_FINI, 0))
1387 strsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1388 if (! elf_add_dynamic_entry (info, DT_HASH, 0)
1389 || ! elf_add_dynamic_entry (info, DT_STRTAB, 0)
1390 || ! elf_add_dynamic_entry (info, DT_SYMTAB, 0)
1391 || ! elf_add_dynamic_entry (info, DT_STRSZ, strsize)
1392 || ! elf_add_dynamic_entry (info, DT_SYMENT,
1393 sizeof (Elf_External_Sym)))
1397 /* The backend must work out the sizes of all the other dynamic
1399 bed = get_elf_backend_data (output_bfd);
1400 if (! (*bed->elf_backend_size_dynamic_sections) (output_bfd, info))
1403 if (elf_hash_table (info)->dynamic_sections_created)
1408 size_t bucketcount = 0;
1409 Elf_Internal_Sym isym;
1411 /* Set the size of the .dynsym and .hash sections. We counted
1412 the number of dynamic symbols in elf_link_add_object_symbols.
1413 We will build the contents of .dynsym and .hash when we build
1414 the final symbol table, because until then we do not know the
1415 correct value to give the symbols. We built the .dynstr
1416 section as we went along in elf_link_add_object_symbols. */
1417 dynsymcount = elf_hash_table (info)->dynsymcount;
1418 s = bfd_get_section_by_name (dynobj, ".dynsym");
1419 BFD_ASSERT (s != NULL);
1420 s->_raw_size = dynsymcount * sizeof (Elf_External_Sym);
1421 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1422 if (s->contents == NULL && s->_raw_size != 0)
1425 /* The first entry in .dynsym is a dummy symbol. */
1432 elf_swap_symbol_out (output_bfd, &isym,
1433 (PTR) (Elf_External_Sym *) s->contents);
1435 for (i = 0; elf_buckets[i] != 0; i++)
1437 bucketcount = elf_buckets[i];
1438 if (dynsymcount < elf_buckets[i + 1])
1442 s = bfd_get_section_by_name (dynobj, ".hash");
1443 BFD_ASSERT (s != NULL);
1444 s->_raw_size = (2 + bucketcount + dynsymcount) * (ARCH_SIZE / 8);
1445 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1446 if (s->contents == NULL)
1448 memset (s->contents, 0, (size_t) s->_raw_size);
1450 put_word (output_bfd, bucketcount, s->contents);
1451 put_word (output_bfd, dynsymcount, s->contents + (ARCH_SIZE / 8));
1453 elf_hash_table (info)->bucketcount = bucketcount;
1455 s = bfd_get_section_by_name (dynobj, ".dynstr");
1456 BFD_ASSERT (s != NULL);
1457 s->_raw_size = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1459 if (! elf_add_dynamic_entry (info, DT_NULL, 0))
1466 /* This routine is used to export all defined symbols into the dynamic
1467 symbol table. It is called via elf_link_hash_traverse. */
1470 elf_export_symbol (h, data)
1471 struct elf_link_hash_entry *h;
1474 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1476 if (h->dynindx == -1
1477 && (h->elf_link_hash_flags
1478 & (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0)
1480 if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h))
1490 /* Make the backend pick a good value for a dynamic symbol. This is
1491 called via elf_link_hash_traverse, and also calls itself
1495 elf_adjust_dynamic_symbol (h, data)
1496 struct elf_link_hash_entry *h;
1499 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1501 struct elf_backend_data *bed;
1503 /* If -Bsymbolic was used (which means to bind references to global
1504 symbols to the definition within the shared object), and this
1505 symbol was defined in a regular object, then it actually doesn't
1506 need a PLT entry. */
1507 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0
1508 && eif->info->shared
1509 && eif->info->symbolic
1510 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1511 h->elf_link_hash_flags &=~ ELF_LINK_HASH_NEEDS_PLT;
1513 /* If this symbol does not require a PLT entry, and it is not
1514 defined by a dynamic object, or is not referenced by a regular
1515 object, ignore it. We do have to handle a weak defined symbol,
1516 even if no regular object refers to it, if we decided to add it
1517 to the dynamic symbol table. FIXME: Do we normally need to worry
1518 about symbols which are defined by one dynamic object and
1519 referenced by another one? */
1520 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0
1521 && ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
1522 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
1523 || ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0
1524 && (h->weakdef == NULL || h->weakdef->dynindx == -1))))
1527 /* If we've already adjusted this symbol, don't do it again. This
1528 can happen via a recursive call. */
1529 if ((h->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0)
1532 /* Don't look at this symbol again. Note that we must set this
1533 after checking the above conditions, because we may look at a
1534 symbol once, decide not to do anything, and then get called
1535 recursively later after REF_REGULAR is set below. */
1536 h->elf_link_hash_flags |= ELF_LINK_HASH_DYNAMIC_ADJUSTED;
1538 /* If this is a weak definition, and we know a real definition, and
1539 the real symbol is not itself defined by a regular object file,
1540 then get a good value for the real definition. We handle the
1541 real symbol first, for the convenience of the backend routine.
1543 Note that there is a confusing case here. If the real definition
1544 is defined by a regular object file, we don't get the real symbol
1545 from the dynamic object, but we do get the weak symbol. If the
1546 processor backend uses a COPY reloc, then if some routine in the
1547 dynamic object changes the real symbol, we will not see that
1548 change in the corresponding weak symbol. This is the way other
1549 ELF linkers work as well, and seems to be a result of the shared
1552 I will clarify this issue. Most SVR4 shared libraries define the
1553 variable _timezone and define timezone as a weak synonym. The
1554 tzset call changes _timezone. If you write
1555 extern int timezone;
1557 int main () { tzset (); printf ("%d %d\n", timezone, _timezone); }
1558 you might expect that, since timezone is a synonym for _timezone,
1559 the same number will print both times. However, if the processor
1560 backend uses a COPY reloc, then actually timezone will be copied
1561 into your process image, and, since you define _timezone
1562 yourself, _timezone will not. Thus timezone and _timezone will
1563 wind up at different memory locations. The tzset call will set
1564 _timezone, leaving timezone unchanged. */
1566 if (h->weakdef != NULL)
1568 struct elf_link_hash_entry *weakdef;
1570 BFD_ASSERT (h->root.type == bfd_link_hash_defined
1571 || h->root.type == bfd_link_hash_defweak);
1572 weakdef = h->weakdef;
1573 BFD_ASSERT (weakdef->root.type == bfd_link_hash_defined
1574 || weakdef->root.type == bfd_link_hash_defweak);
1575 BFD_ASSERT (weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC);
1576 if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1578 /* This symbol is defined by a regular object file, so we
1579 will not do anything special. Clear weakdef for the
1580 convenience of the processor backend. */
1585 /* There is an implicit reference by a regular object file
1586 via the weak symbol. */
1587 weakdef->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR;
1588 if (! elf_adjust_dynamic_symbol (weakdef, (PTR) eif))
1593 dynobj = elf_hash_table (eif->info)->dynobj;
1594 bed = get_elf_backend_data (dynobj);
1595 if (! (*bed->elf_backend_adjust_dynamic_symbol) (eif->info, h))
1604 /* Final phase of ELF linker. */
1606 /* A structure we use to avoid passing large numbers of arguments. */
1608 struct elf_final_link_info
1610 /* General link information. */
1611 struct bfd_link_info *info;
1614 /* Symbol string table. */
1615 struct bfd_strtab_hash *symstrtab;
1616 /* .dynsym section. */
1617 asection *dynsym_sec;
1618 /* .hash section. */
1620 /* Buffer large enough to hold contents of any section. */
1622 /* Buffer large enough to hold external relocs of any section. */
1623 PTR external_relocs;
1624 /* Buffer large enough to hold internal relocs of any section. */
1625 Elf_Internal_Rela *internal_relocs;
1626 /* Buffer large enough to hold external local symbols of any input
1628 Elf_External_Sym *external_syms;
1629 /* Buffer large enough to hold internal local symbols of any input
1631 Elf_Internal_Sym *internal_syms;
1632 /* Array large enough to hold a symbol index for each local symbol
1633 of any input BFD. */
1635 /* Array large enough to hold a section pointer for each local
1636 symbol of any input BFD. */
1637 asection **sections;
1638 /* Buffer to hold swapped out symbols. */
1639 Elf_External_Sym *symbuf;
1640 /* Number of swapped out symbols in buffer. */
1641 size_t symbuf_count;
1642 /* Number of symbols which fit in symbuf. */
1646 static boolean elf_link_output_sym
1647 PARAMS ((struct elf_final_link_info *, const char *,
1648 Elf_Internal_Sym *, asection *));
1649 static boolean elf_link_flush_output_syms
1650 PARAMS ((struct elf_final_link_info *));
1651 static boolean elf_link_output_extsym
1652 PARAMS ((struct elf_link_hash_entry *, PTR));
1653 static boolean elf_link_input_bfd
1654 PARAMS ((struct elf_final_link_info *, bfd *));
1655 static boolean elf_reloc_link_order
1656 PARAMS ((bfd *, struct bfd_link_info *, asection *,
1657 struct bfd_link_order *));
1659 /* This struct is used to pass information to routines called via
1660 elf_link_hash_traverse which must return failure. */
1662 struct elf_finfo_failed
1665 struct elf_final_link_info *finfo;
1668 /* Do the final step of an ELF link. */
1671 elf_bfd_final_link (abfd, info)
1673 struct bfd_link_info *info;
1677 struct elf_final_link_info finfo;
1678 register asection *o;
1679 register struct bfd_link_order *p;
1681 size_t max_contents_size;
1682 size_t max_external_reloc_size;
1683 size_t max_internal_reloc_count;
1684 size_t max_sym_count;
1686 Elf_Internal_Sym elfsym;
1688 Elf_Internal_Shdr *symtab_hdr;
1689 Elf_Internal_Shdr *symstrtab_hdr;
1690 struct elf_backend_data *bed = get_elf_backend_data (abfd);
1691 struct elf_finfo_failed eif;
1694 abfd->flags |= DYNAMIC;
1696 dynamic = elf_hash_table (info)->dynamic_sections_created;
1697 dynobj = elf_hash_table (info)->dynobj;
1700 finfo.output_bfd = abfd;
1701 finfo.symstrtab = elf_stringtab_init ();
1702 if (finfo.symstrtab == NULL)
1706 finfo.dynsym_sec = NULL;
1707 finfo.hash_sec = NULL;
1711 finfo.dynsym_sec = bfd_get_section_by_name (dynobj, ".dynsym");
1712 finfo.hash_sec = bfd_get_section_by_name (dynobj, ".hash");
1713 BFD_ASSERT (finfo.dynsym_sec != NULL && finfo.hash_sec != NULL);
1715 finfo.contents = NULL;
1716 finfo.external_relocs = NULL;
1717 finfo.internal_relocs = NULL;
1718 finfo.external_syms = NULL;
1719 finfo.internal_syms = NULL;
1720 finfo.indices = NULL;
1721 finfo.sections = NULL;
1722 finfo.symbuf = NULL;
1723 finfo.symbuf_count = 0;
1725 /* Count up the number of relocations we will output for each output
1726 section, so that we know the sizes of the reloc sections. We
1727 also figure out some maximum sizes. */
1728 max_contents_size = 0;
1729 max_external_reloc_size = 0;
1730 max_internal_reloc_count = 0;
1732 for (o = abfd->sections; o != (asection *) NULL; o = o->next)
1736 for (p = o->link_order_head; p != NULL; p = p->next)
1738 if (p->type == bfd_section_reloc_link_order
1739 || p->type == bfd_symbol_reloc_link_order)
1741 else if (p->type == bfd_indirect_link_order)
1745 sec = p->u.indirect.section;
1747 if (info->relocateable)
1748 o->reloc_count += sec->reloc_count;
1750 if (sec->_raw_size > max_contents_size)
1751 max_contents_size = sec->_raw_size;
1752 if (sec->_cooked_size > max_contents_size)
1753 max_contents_size = sec->_cooked_size;
1755 /* We are interested in just local symbols, not all
1757 if (bfd_get_flavour (sec->owner) == bfd_target_elf_flavour)
1761 if (elf_bad_symtab (sec->owner))
1762 sym_count = (elf_tdata (sec->owner)->symtab_hdr.sh_size
1763 / sizeof (Elf_External_Sym));
1765 sym_count = elf_tdata (sec->owner)->symtab_hdr.sh_info;
1767 if (sym_count > max_sym_count)
1768 max_sym_count = sym_count;
1770 if ((sec->flags & SEC_RELOC) != 0)
1774 ext_size = elf_section_data (sec)->rel_hdr.sh_size;
1775 if (ext_size > max_external_reloc_size)
1776 max_external_reloc_size = ext_size;
1777 if (sec->reloc_count > max_internal_reloc_count)
1778 max_internal_reloc_count = sec->reloc_count;
1784 if (o->reloc_count > 0)
1785 o->flags |= SEC_RELOC;
1788 /* Explicitly clear the SEC_RELOC flag. The linker tends to
1789 set it (this is probably a bug) and if it is set
1790 assign_section_numbers will create a reloc section. */
1791 o->flags &=~ SEC_RELOC;
1794 /* If the SEC_ALLOC flag is not set, force the section VMA to
1795 zero. This is done in elf_fake_sections as well, but forcing
1796 the VMA to 0 here will ensure that relocs against these
1797 sections are handled correctly. */
1798 if ((o->flags & SEC_ALLOC) == 0)
1802 /* Figure out the file positions for everything but the symbol table
1803 and the relocs. We set symcount to force assign_section_numbers
1804 to create a symbol table. */
1805 abfd->symcount = info->strip == strip_all ? 0 : 1;
1806 BFD_ASSERT (! abfd->output_has_begun);
1807 if (! _bfd_elf_compute_section_file_positions (abfd, info))
1810 /* That created the reloc sections. Set their sizes, and assign
1811 them file positions, and allocate some buffers. */
1812 for (o = abfd->sections; o != NULL; o = o->next)
1814 if ((o->flags & SEC_RELOC) != 0)
1816 Elf_Internal_Shdr *rel_hdr;
1817 register struct elf_link_hash_entry **p, **pend;
1819 rel_hdr = &elf_section_data (o)->rel_hdr;
1821 rel_hdr->sh_size = rel_hdr->sh_entsize * o->reloc_count;
1823 /* The contents field must last into write_object_contents,
1824 so we allocate it with bfd_alloc rather than malloc. */
1825 rel_hdr->contents = (PTR) bfd_alloc (abfd, rel_hdr->sh_size);
1826 if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0)
1829 p = ((struct elf_link_hash_entry **)
1830 bfd_malloc (o->reloc_count
1831 * sizeof (struct elf_link_hash_entry *)));
1832 if (p == NULL && o->reloc_count != 0)
1834 elf_section_data (o)->rel_hashes = p;
1835 pend = p + o->reloc_count;
1836 for (; p < pend; p++)
1839 /* Use the reloc_count field as an index when outputting the
1845 _bfd_elf_assign_file_positions_for_relocs (abfd);
1847 /* We have now assigned file positions for all the sections except
1848 .symtab and .strtab. We start the .symtab section at the current
1849 file position, and write directly to it. We build the .strtab
1850 section in memory. */
1852 symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
1853 /* sh_name is set in prep_headers. */
1854 symtab_hdr->sh_type = SHT_SYMTAB;
1855 symtab_hdr->sh_flags = 0;
1856 symtab_hdr->sh_addr = 0;
1857 symtab_hdr->sh_size = 0;
1858 symtab_hdr->sh_entsize = sizeof (Elf_External_Sym);
1859 /* sh_link is set in assign_section_numbers. */
1860 /* sh_info is set below. */
1861 /* sh_offset is set just below. */
1862 symtab_hdr->sh_addralign = 4; /* FIXME: system dependent? */
1864 off = elf_tdata (abfd)->next_file_pos;
1865 off = _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true);
1867 /* Note that at this point elf_tdata (abfd)->next_file_pos is
1868 incorrect. We do not yet know the size of the .symtab section.
1869 We correct next_file_pos below, after we do know the size. */
1871 /* Allocate a buffer to hold swapped out symbols. This is to avoid
1872 continuously seeking to the right position in the file. */
1873 if (! info->keep_memory || max_sym_count < 20)
1874 finfo.symbuf_size = 20;
1876 finfo.symbuf_size = max_sym_count;
1877 finfo.symbuf = ((Elf_External_Sym *)
1878 bfd_malloc (finfo.symbuf_size * sizeof (Elf_External_Sym)));
1879 if (finfo.symbuf == NULL)
1882 /* Start writing out the symbol table. The first symbol is always a
1884 elfsym.st_value = 0;
1887 elfsym.st_other = 0;
1888 elfsym.st_shndx = SHN_UNDEF;
1889 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1890 &elfsym, bfd_und_section_ptr))
1894 /* Some standard ELF linkers do this, but we don't because it causes
1895 bootstrap comparison failures. */
1896 /* Output a file symbol for the output file as the second symbol.
1897 We output this even if we are discarding local symbols, although
1898 I'm not sure if this is correct. */
1899 elfsym.st_value = 0;
1901 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_FILE);
1902 elfsym.st_other = 0;
1903 elfsym.st_shndx = SHN_ABS;
1904 if (! elf_link_output_sym (&finfo, bfd_get_filename (abfd),
1905 &elfsym, bfd_abs_section_ptr))
1909 /* Output a symbol for each section. We output these even if we are
1910 discarding local symbols, since they are used for relocs. These
1911 symbols have no names. We store the index of each one in the
1912 index field of the section, so that we can find it again when
1913 outputting relocs. */
1914 elfsym.st_value = 0;
1916 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION);
1917 elfsym.st_other = 0;
1918 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
1920 o = section_from_elf_index (abfd, i);
1922 o->target_index = abfd->symcount;
1923 elfsym.st_shndx = i;
1924 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1929 /* Allocate some memory to hold information read in from the input
1931 finfo.contents = (bfd_byte *) bfd_malloc (max_contents_size);
1932 finfo.external_relocs = (PTR) bfd_malloc (max_external_reloc_size);
1933 finfo.internal_relocs = ((Elf_Internal_Rela *)
1934 bfd_malloc (max_internal_reloc_count
1935 * sizeof (Elf_Internal_Rela)));
1936 finfo.external_syms = ((Elf_External_Sym *)
1937 bfd_malloc (max_sym_count
1938 * sizeof (Elf_External_Sym)));
1939 finfo.internal_syms = ((Elf_Internal_Sym *)
1940 bfd_malloc (max_sym_count
1941 * sizeof (Elf_Internal_Sym)));
1942 finfo.indices = (long *) bfd_malloc (max_sym_count * sizeof (long));
1943 finfo.sections = ((asection **)
1944 bfd_malloc (max_sym_count * sizeof (asection *)));
1945 if ((finfo.contents == NULL && max_contents_size != 0)
1946 || (finfo.external_relocs == NULL && max_external_reloc_size != 0)
1947 || (finfo.internal_relocs == NULL && max_internal_reloc_count != 0)
1948 || (finfo.external_syms == NULL && max_sym_count != 0)
1949 || (finfo.internal_syms == NULL && max_sym_count != 0)
1950 || (finfo.indices == NULL && max_sym_count != 0)
1951 || (finfo.sections == NULL && max_sym_count != 0))
1954 /* Since ELF permits relocations to be against local symbols, we
1955 must have the local symbols available when we do the relocations.
1956 Since we would rather only read the local symbols once, and we
1957 would rather not keep them in memory, we handle all the
1958 relocations for a single input file at the same time.
1960 Unfortunately, there is no way to know the total number of local
1961 symbols until we have seen all of them, and the local symbol
1962 indices precede the global symbol indices. This means that when
1963 we are generating relocateable output, and we see a reloc against
1964 a global symbol, we can not know the symbol index until we have
1965 finished examining all the local symbols to see which ones we are
1966 going to output. To deal with this, we keep the relocations in
1967 memory, and don't output them until the end of the link. This is
1968 an unfortunate waste of memory, but I don't see a good way around
1969 it. Fortunately, it only happens when performing a relocateable
1970 link, which is not the common case. FIXME: If keep_memory is set
1971 we could write the relocs out and then read them again; I don't
1972 know how bad the memory loss will be. */
1974 for (sub = info->input_bfds; sub != NULL; sub = sub->next)
1975 sub->output_has_begun = false;
1976 for (o = abfd->sections; o != NULL; o = o->next)
1978 for (p = o->link_order_head; p != NULL; p = p->next)
1980 if (p->type == bfd_indirect_link_order
1981 && (bfd_get_flavour (p->u.indirect.section->owner)
1982 == bfd_target_elf_flavour))
1984 sub = p->u.indirect.section->owner;
1985 if (! sub->output_has_begun)
1987 if (! elf_link_input_bfd (&finfo, sub))
1989 sub->output_has_begun = true;
1992 else if (p->type == bfd_section_reloc_link_order
1993 || p->type == bfd_symbol_reloc_link_order)
1995 if (! elf_reloc_link_order (abfd, info, o, p))
2000 if (! _bfd_default_link_order (abfd, info, o, p))
2006 /* That wrote out all the local symbols. Finish up the symbol table
2007 with the global symbols. */
2009 /* The sh_info field records the index of the first non local
2011 symtab_hdr->sh_info = abfd->symcount;
2013 elf_section_data (finfo.dynsym_sec->output_section)->this_hdr.sh_info = 1;
2015 /* We get the global symbols from the hash table. */
2018 elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym,
2023 /* Flush all symbols to the file. */
2024 if (! elf_link_flush_output_syms (&finfo))
2027 /* Now we know the size of the symtab section. */
2028 off += symtab_hdr->sh_size;
2030 /* Finish up and write out the symbol string table (.strtab)
2032 symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr;
2033 /* sh_name was set in prep_headers. */
2034 symstrtab_hdr->sh_type = SHT_STRTAB;
2035 symstrtab_hdr->sh_flags = 0;
2036 symstrtab_hdr->sh_addr = 0;
2037 symstrtab_hdr->sh_size = _bfd_stringtab_size (finfo.symstrtab);
2038 symstrtab_hdr->sh_entsize = 0;
2039 symstrtab_hdr->sh_link = 0;
2040 symstrtab_hdr->sh_info = 0;
2041 /* sh_offset is set just below. */
2042 symstrtab_hdr->sh_addralign = 1;
2044 off = _bfd_elf_assign_file_position_for_section (symstrtab_hdr, off, true);
2045 elf_tdata (abfd)->next_file_pos = off;
2047 if (bfd_seek (abfd, symstrtab_hdr->sh_offset, SEEK_SET) != 0
2048 || ! _bfd_stringtab_emit (abfd, finfo.symstrtab))
2051 /* Adjust the relocs to have the correct symbol indices. */
2052 for (o = abfd->sections; o != NULL; o = o->next)
2054 struct elf_link_hash_entry **rel_hash;
2055 Elf_Internal_Shdr *rel_hdr;
2057 if ((o->flags & SEC_RELOC) == 0)
2060 rel_hash = elf_section_data (o)->rel_hashes;
2061 rel_hdr = &elf_section_data (o)->rel_hdr;
2062 for (i = 0; i < o->reloc_count; i++, rel_hash++)
2064 if (*rel_hash == NULL)
2067 BFD_ASSERT ((*rel_hash)->indx >= 0);
2069 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2071 Elf_External_Rel *erel;
2072 Elf_Internal_Rel irel;
2074 erel = (Elf_External_Rel *) rel_hdr->contents + i;
2075 elf_swap_reloc_in (abfd, erel, &irel);
2076 irel.r_info = ELF_R_INFO ((*rel_hash)->indx,
2077 ELF_R_TYPE (irel.r_info));
2078 elf_swap_reloc_out (abfd, &irel, erel);
2082 Elf_External_Rela *erela;
2083 Elf_Internal_Rela irela;
2085 BFD_ASSERT (rel_hdr->sh_entsize
2086 == sizeof (Elf_External_Rela));
2088 erela = (Elf_External_Rela *) rel_hdr->contents + i;
2089 elf_swap_reloca_in (abfd, erela, &irela);
2090 irela.r_info = ELF_R_INFO ((*rel_hash)->indx,
2091 ELF_R_TYPE (irela.r_info));
2092 elf_swap_reloca_out (abfd, &irela, erela);
2096 /* Set the reloc_count field to 0 to prevent write_relocs from
2097 trying to swap the relocs out itself. */
2101 /* If we are linking against a dynamic object, or generating a
2102 shared library, finish up the dynamic linking information. */
2105 Elf_External_Dyn *dyncon, *dynconend;
2107 /* Fix up .dynamic entries. */
2108 o = bfd_get_section_by_name (dynobj, ".dynamic");
2109 BFD_ASSERT (o != NULL);
2111 dyncon = (Elf_External_Dyn *) o->contents;
2112 dynconend = (Elf_External_Dyn *) (o->contents + o->_raw_size);
2113 for (; dyncon < dynconend; dyncon++)
2115 Elf_Internal_Dyn dyn;
2119 elf_swap_dyn_in (dynobj, dyncon, &dyn);
2126 /* SVR4 linkers seem to set DT_INIT and DT_FINI based on
2127 magic _init and _fini symbols. This is pretty ugly,
2128 but we are compatible. */
2136 struct elf_link_hash_entry *h;
2138 h = elf_link_hash_lookup (elf_hash_table (info), name,
2139 false, false, true);
2141 && (h->root.type == bfd_link_hash_defined
2142 || h->root.type == bfd_link_hash_defweak))
2144 dyn.d_un.d_val = h->root.u.def.value;
2145 o = h->root.u.def.section;
2146 if (o->output_section != NULL)
2147 dyn.d_un.d_val += (o->output_section->vma
2148 + o->output_offset);
2151 /* The symbol is imported from another shared
2152 library and does not apply to this one. */
2156 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2170 o = bfd_get_section_by_name (abfd, name);
2171 BFD_ASSERT (o != NULL);
2172 dyn.d_un.d_ptr = o->vma;
2173 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2180 if (dyn.d_tag == DT_REL || dyn.d_tag == DT_RELSZ)
2185 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
2187 Elf_Internal_Shdr *hdr;
2189 hdr = elf_elfsections (abfd)[i];
2190 if (hdr->sh_type == type
2191 && (hdr->sh_flags & SHF_ALLOC) != 0)
2193 if (dyn.d_tag == DT_RELSZ || dyn.d_tag == DT_RELASZ)
2194 dyn.d_un.d_val += hdr->sh_size;
2197 if (dyn.d_un.d_val == 0
2198 || hdr->sh_addr < dyn.d_un.d_val)
2199 dyn.d_un.d_val = hdr->sh_addr;
2203 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2209 /* If we have created any dynamic sections, then output them. */
2212 if (! (*bed->elf_backend_finish_dynamic_sections) (abfd, info))
2215 for (o = dynobj->sections; o != NULL; o = o->next)
2217 if ((o->flags & SEC_HAS_CONTENTS) == 0
2218 || o->_raw_size == 0)
2220 if ((o->flags & SEC_IN_MEMORY) == 0)
2222 /* At this point, we are only interested in sections
2223 created by elf_link_create_dynamic_sections. FIXME:
2224 This test is fragile. */
2227 if ((elf_section_data (o->output_section)->this_hdr.sh_type
2229 || strcmp (bfd_get_section_name (abfd, o), ".dynstr") != 0)
2231 if (! bfd_set_section_contents (abfd, o->output_section,
2232 o->contents, o->output_offset,
2240 /* The contents of the .dynstr section are actually in a
2242 off = elf_section_data (o->output_section)->this_hdr.sh_offset;
2243 if (bfd_seek (abfd, off, SEEK_SET) != 0
2244 || ! _bfd_stringtab_emit (abfd,
2245 elf_hash_table (info)->dynstr))
2251 if (finfo.symstrtab != NULL)
2252 _bfd_stringtab_free (finfo.symstrtab);
2253 if (finfo.contents != NULL)
2254 free (finfo.contents);
2255 if (finfo.external_relocs != NULL)
2256 free (finfo.external_relocs);
2257 if (finfo.internal_relocs != NULL)
2258 free (finfo.internal_relocs);
2259 if (finfo.external_syms != NULL)
2260 free (finfo.external_syms);
2261 if (finfo.internal_syms != NULL)
2262 free (finfo.internal_syms);
2263 if (finfo.indices != NULL)
2264 free (finfo.indices);
2265 if (finfo.sections != NULL)
2266 free (finfo.sections);
2267 if (finfo.symbuf != NULL)
2268 free (finfo.symbuf);
2269 for (o = abfd->sections; o != NULL; o = o->next)
2271 if ((o->flags & SEC_RELOC) != 0
2272 && elf_section_data (o)->rel_hashes != NULL)
2273 free (elf_section_data (o)->rel_hashes);
2276 elf_tdata (abfd)->linker = true;
2281 if (finfo.symstrtab != NULL)
2282 _bfd_stringtab_free (finfo.symstrtab);
2283 if (finfo.contents != NULL)
2284 free (finfo.contents);
2285 if (finfo.external_relocs != NULL)
2286 free (finfo.external_relocs);
2287 if (finfo.internal_relocs != NULL)
2288 free (finfo.internal_relocs);
2289 if (finfo.external_syms != NULL)
2290 free (finfo.external_syms);
2291 if (finfo.internal_syms != NULL)
2292 free (finfo.internal_syms);
2293 if (finfo.indices != NULL)
2294 free (finfo.indices);
2295 if (finfo.sections != NULL)
2296 free (finfo.sections);
2297 if (finfo.symbuf != NULL)
2298 free (finfo.symbuf);
2299 for (o = abfd->sections; o != NULL; o = o->next)
2301 if ((o->flags & SEC_RELOC) != 0
2302 && elf_section_data (o)->rel_hashes != NULL)
2303 free (elf_section_data (o)->rel_hashes);
2309 /* Add a symbol to the output symbol table. */
2312 elf_link_output_sym (finfo, name, elfsym, input_sec)
2313 struct elf_final_link_info *finfo;
2315 Elf_Internal_Sym *elfsym;
2316 asection *input_sec;
2318 boolean (*output_symbol_hook) PARAMS ((bfd *,
2319 struct bfd_link_info *info,
2324 output_symbol_hook = get_elf_backend_data (finfo->output_bfd)->
2325 elf_backend_link_output_symbol_hook;
2326 if (output_symbol_hook != NULL)
2328 if (! ((*output_symbol_hook)
2329 (finfo->output_bfd, finfo->info, name, elfsym, input_sec)))
2333 if (name == (const char *) NULL || *name == '\0')
2334 elfsym->st_name = 0;
2337 elfsym->st_name = (unsigned long) _bfd_stringtab_add (finfo->symstrtab,
2340 if (elfsym->st_name == (unsigned long) -1)
2344 if (finfo->symbuf_count >= finfo->symbuf_size)
2346 if (! elf_link_flush_output_syms (finfo))
2350 elf_swap_symbol_out (finfo->output_bfd, elfsym,
2351 (PTR) (finfo->symbuf + finfo->symbuf_count));
2352 ++finfo->symbuf_count;
2354 ++finfo->output_bfd->symcount;
2359 /* Flush the output symbols to the file. */
2362 elf_link_flush_output_syms (finfo)
2363 struct elf_final_link_info *finfo;
2365 Elf_Internal_Shdr *symtab;
2367 symtab = &elf_tdata (finfo->output_bfd)->symtab_hdr;
2369 if (bfd_seek (finfo->output_bfd, symtab->sh_offset + symtab->sh_size,
2371 || (bfd_write ((PTR) finfo->symbuf, finfo->symbuf_count,
2372 sizeof (Elf_External_Sym), finfo->output_bfd)
2373 != finfo->symbuf_count * sizeof (Elf_External_Sym)))
2376 symtab->sh_size += finfo->symbuf_count * sizeof (Elf_External_Sym);
2378 finfo->symbuf_count = 0;
2383 /* Add an external symbol to the symbol table. This is called from
2384 the hash table traversal routine. */
2387 elf_link_output_extsym (h, data)
2388 struct elf_link_hash_entry *h;
2391 struct elf_finfo_failed *eif = (struct elf_finfo_failed *) data;
2392 struct elf_final_link_info *finfo = eif->finfo;
2394 Elf_Internal_Sym sym;
2395 asection *input_sec;
2397 /* If we are not creating a shared library, and this symbol is
2398 referenced by a shared library but is not defined anywhere, then
2399 warn that it is undefined. If we do not do this, the runtime
2400 linker will complain that the symbol is undefined when the
2401 program is run. We don't have to worry about symbols that are
2402 referenced by regular files, because we will already have issued
2403 warnings for them. */
2404 if (! finfo->info->relocateable
2405 && ! finfo->info->shared
2406 && h->root.type == bfd_link_hash_undefined
2407 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0
2408 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2410 if (! ((*finfo->info->callbacks->undefined_symbol)
2411 (finfo->info, h->root.root.string, h->root.u.undef.abfd,
2412 (asection *) NULL, 0)))
2419 /* We don't want to output symbols that have never been mentioned by
2420 a regular file, or that we have been told to strip. However, if
2421 h->indx is set to -2, the symbol is used by a reloc and we must
2425 else if (((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
2426 || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)
2427 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0
2428 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2430 else if (finfo->info->strip == strip_all
2431 || (finfo->info->strip == strip_some
2432 && bfd_hash_lookup (finfo->info->keep_hash,
2433 h->root.root.string,
2434 false, false) == NULL))
2439 /* If we're stripping it, and it's not a dynamic symbol, there's
2440 nothing else to do. */
2441 if (strip && h->dynindx == -1)
2445 sym.st_size = h->size;
2447 if (h->root.type == bfd_link_hash_undefweak
2448 || h->root.type == bfd_link_hash_defweak)
2449 sym.st_info = ELF_ST_INFO (STB_WEAK, h->type);
2451 sym.st_info = ELF_ST_INFO (STB_GLOBAL, h->type);
2453 switch (h->root.type)
2456 case bfd_link_hash_new:
2460 case bfd_link_hash_undefined:
2461 input_sec = bfd_und_section_ptr;
2462 sym.st_shndx = SHN_UNDEF;
2465 case bfd_link_hash_undefweak:
2466 input_sec = bfd_und_section_ptr;
2467 sym.st_shndx = SHN_UNDEF;
2470 case bfd_link_hash_defined:
2471 case bfd_link_hash_defweak:
2473 input_sec = h->root.u.def.section;
2474 if (input_sec->output_section != NULL)
2477 _bfd_elf_section_from_bfd_section (finfo->output_bfd,
2478 input_sec->output_section);
2479 if (sym.st_shndx == (unsigned short) -1)
2485 /* ELF symbols in relocateable files are section relative,
2486 but in nonrelocateable files they are virtual
2488 sym.st_value = h->root.u.def.value + input_sec->output_offset;
2489 if (! finfo->info->relocateable)
2490 sym.st_value += input_sec->output_section->vma;
2494 BFD_ASSERT ((bfd_get_flavour (input_sec->owner)
2495 == bfd_target_elf_flavour)
2496 && elf_elfheader (input_sec->owner)->e_type == ET_DYN);
2497 sym.st_shndx = SHN_UNDEF;
2498 input_sec = bfd_und_section_ptr;
2503 case bfd_link_hash_common:
2504 input_sec = bfd_com_section_ptr;
2505 sym.st_shndx = SHN_COMMON;
2506 sym.st_value = 1 << h->root.u.c.p->alignment_power;
2509 case bfd_link_hash_indirect:
2510 case bfd_link_hash_warning:
2511 /* We can't represent these symbols in ELF. A warning symbol
2512 may have come from a .gnu.warning.SYMBOL section anyhow. We
2513 just put the target symbol in the hash table. If the target
2514 symbol does not really exist, don't do anything. */
2515 if (h->root.u.i.link->type == bfd_link_hash_new)
2517 return (elf_link_output_extsym
2518 ((struct elf_link_hash_entry *) h->root.u.i.link, data));
2521 /* If this symbol should be put in the .dynsym section, then put it
2522 there now. We have already know the symbol index. We also fill
2523 in the entry in the .hash section. */
2524 if (h->dynindx != -1
2525 && elf_hash_table (finfo->info)->dynamic_sections_created)
2527 struct elf_backend_data *bed;
2530 bfd_byte *bucketpos;
2533 sym.st_name = h->dynstr_index;
2535 /* Give the processor backend a chance to tweak the symbol
2536 value, and also to finish up anything that needs to be done
2538 bed = get_elf_backend_data (finfo->output_bfd);
2539 if (! ((*bed->elf_backend_finish_dynamic_symbol)
2540 (finfo->output_bfd, finfo->info, h, &sym)))
2546 elf_swap_symbol_out (finfo->output_bfd, &sym,
2547 (PTR) (((Elf_External_Sym *)
2548 finfo->dynsym_sec->contents)
2551 bucketcount = elf_hash_table (finfo->info)->bucketcount;
2552 bucket = (bfd_elf_hash ((const unsigned char *) h->root.root.string)
2554 bucketpos = ((bfd_byte *) finfo->hash_sec->contents
2555 + (bucket + 2) * (ARCH_SIZE / 8));
2556 chain = get_word (finfo->output_bfd, bucketpos);
2557 put_word (finfo->output_bfd, h->dynindx, bucketpos);
2558 put_word (finfo->output_bfd, chain,
2559 ((bfd_byte *) finfo->hash_sec->contents
2560 + (bucketcount + 2 + h->dynindx) * (ARCH_SIZE / 8)));
2563 /* If we're stripping it, then it was just a dynamic symbol, and
2564 there's nothing else to do. */
2568 h->indx = finfo->output_bfd->symcount;
2570 if (! elf_link_output_sym (finfo, h->root.root.string, &sym, input_sec))
2579 /* Link an input file into the linker output file. This function
2580 handles all the sections and relocations of the input file at once.
2581 This is so that we only have to read the local symbols once, and
2582 don't have to keep them in memory. */
2585 elf_link_input_bfd (finfo, input_bfd)
2586 struct elf_final_link_info *finfo;
2589 boolean (*relocate_section) PARAMS ((bfd *, struct bfd_link_info *,
2590 bfd *, asection *, bfd_byte *,
2591 Elf_Internal_Rela *,
2592 Elf_Internal_Sym *, asection **));
2594 Elf_Internal_Shdr *symtab_hdr;
2597 Elf_External_Sym *esym;
2598 Elf_External_Sym *esymend;
2599 Elf_Internal_Sym *isym;
2601 asection **ppsection;
2604 output_bfd = finfo->output_bfd;
2606 get_elf_backend_data (output_bfd)->elf_backend_relocate_section;
2608 /* If this is a dynamic object, we don't want to do anything here:
2609 we don't want the local symbols, and we don't want the section
2611 if (elf_elfheader (input_bfd)->e_type == ET_DYN)
2614 symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
2615 if (elf_bad_symtab (input_bfd))
2617 locsymcount = symtab_hdr->sh_size / sizeof (Elf_External_Sym);
2622 locsymcount = symtab_hdr->sh_info;
2623 extsymoff = symtab_hdr->sh_info;
2626 /* Read the local symbols. */
2628 && (bfd_seek (input_bfd, symtab_hdr->sh_offset, SEEK_SET) != 0
2629 || (bfd_read (finfo->external_syms, sizeof (Elf_External_Sym),
2630 locsymcount, input_bfd)
2631 != locsymcount * sizeof (Elf_External_Sym))))
2634 /* Swap in the local symbols and write out the ones which we know
2635 are going into the output file. */
2636 esym = finfo->external_syms;
2637 esymend = esym + locsymcount;
2638 isym = finfo->internal_syms;
2639 pindex = finfo->indices;
2640 ppsection = finfo->sections;
2641 for (; esym < esymend; esym++, isym++, pindex++, ppsection++)
2645 Elf_Internal_Sym osym;
2647 elf_swap_symbol_in (input_bfd, esym, isym);
2650 if (elf_bad_symtab (input_bfd))
2652 if (ELF_ST_BIND (isym->st_info) != STB_LOCAL)
2659 if (isym->st_shndx == SHN_UNDEF)
2660 isec = bfd_und_section_ptr;
2661 else if (isym->st_shndx > 0 && isym->st_shndx < SHN_LORESERVE)
2662 isec = section_from_elf_index (input_bfd, isym->st_shndx);
2663 else if (isym->st_shndx == SHN_ABS)
2664 isec = bfd_abs_section_ptr;
2665 else if (isym->st_shndx == SHN_COMMON)
2666 isec = bfd_com_section_ptr;
2675 /* Don't output the first, undefined, symbol. */
2676 if (esym == finfo->external_syms)
2679 /* If we are stripping all symbols, we don't want to output this
2681 if (finfo->info->strip == strip_all)
2684 /* We never output section symbols. Instead, we use the section
2685 symbol of the corresponding section in the output file. */
2686 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2689 /* If we are discarding all local symbols, we don't want to
2690 output this one. If we are generating a relocateable output
2691 file, then some of the local symbols may be required by
2692 relocs; we output them below as we discover that they are
2694 if (finfo->info->discard == discard_all)
2697 /* Get the name of the symbol. */
2698 name = bfd_elf_string_from_elf_section (input_bfd, symtab_hdr->sh_link,
2703 /* See if we are discarding symbols with this name. */
2704 if ((finfo->info->strip == strip_some
2705 && (bfd_hash_lookup (finfo->info->keep_hash, name, false, false)
2707 || (finfo->info->discard == discard_l
2708 && strncmp (name, finfo->info->lprefix,
2709 finfo->info->lprefix_len) == 0))
2712 /* If we get here, we are going to output this symbol. */
2716 /* Adjust the section index for the output file. */
2717 osym.st_shndx = _bfd_elf_section_from_bfd_section (output_bfd,
2718 isec->output_section);
2719 if (osym.st_shndx == (unsigned short) -1)
2722 *pindex = output_bfd->symcount;
2724 /* ELF symbols in relocateable files are section relative, but
2725 in executable files they are virtual addresses. Note that
2726 this code assumes that all ELF sections have an associated
2727 BFD section with a reasonable value for output_offset; below
2728 we assume that they also have a reasonable value for
2729 output_section. Any special sections must be set up to meet
2730 these requirements. */
2731 osym.st_value += isec->output_offset;
2732 if (! finfo->info->relocateable)
2733 osym.st_value += isec->output_section->vma;
2735 if (! elf_link_output_sym (finfo, name, &osym, isec))
2739 /* Relocate the contents of each section. */
2740 for (o = input_bfd->sections; o != NULL; o = o->next)
2742 if ((o->flags & SEC_HAS_CONTENTS) == 0)
2745 if ((o->flags & SEC_IN_MEMORY) != 0
2746 && input_bfd == elf_hash_table (finfo->info)->dynobj)
2748 /* Section was created by elf_link_create_dynamic_sections.
2749 FIXME: This test is fragile. */
2753 /* Read the contents of the section. */
2754 if (! bfd_get_section_contents (input_bfd, o, finfo->contents,
2755 (file_ptr) 0, o->_raw_size))
2758 if ((o->flags & SEC_RELOC) != 0)
2760 Elf_Internal_Rela *internal_relocs;
2762 /* Get the swapped relocs. */
2763 internal_relocs = elf_link_read_relocs (input_bfd, o,
2764 finfo->external_relocs,
2765 finfo->internal_relocs,
2767 if (internal_relocs == NULL
2768 && o->reloc_count > 0)
2771 /* Relocate the section by invoking a back end routine.
2773 The back end routine is responsible for adjusting the
2774 section contents as necessary, and (if using Rela relocs
2775 and generating a relocateable output file) adjusting the
2776 reloc addend as necessary.
2778 The back end routine does not have to worry about setting
2779 the reloc address or the reloc symbol index.
2781 The back end routine is given a pointer to the swapped in
2782 internal symbols, and can access the hash table entries
2783 for the external symbols via elf_sym_hashes (input_bfd).
2785 When generating relocateable output, the back end routine
2786 must handle STB_LOCAL/STT_SECTION symbols specially. The
2787 output symbol is going to be a section symbol
2788 corresponding to the output section, which will require
2789 the addend to be adjusted. */
2791 if (! (*relocate_section) (output_bfd, finfo->info,
2795 finfo->internal_syms,
2799 if (finfo->info->relocateable)
2801 Elf_Internal_Rela *irela;
2802 Elf_Internal_Rela *irelaend;
2803 struct elf_link_hash_entry **rel_hash;
2804 Elf_Internal_Shdr *input_rel_hdr;
2805 Elf_Internal_Shdr *output_rel_hdr;
2807 /* Adjust the reloc addresses and symbol indices. */
2809 irela = internal_relocs;
2810 irelaend = irela + o->reloc_count;
2811 rel_hash = (elf_section_data (o->output_section)->rel_hashes
2812 + o->output_section->reloc_count);
2813 for (; irela < irelaend; irela++, rel_hash++)
2815 unsigned long r_symndx;
2816 Elf_Internal_Sym *isym;
2819 irela->r_offset += o->output_offset;
2821 r_symndx = ELF_R_SYM (irela->r_info);
2826 if (r_symndx >= locsymcount
2827 || (elf_bad_symtab (input_bfd)
2828 && finfo->sections[r_symndx] == NULL))
2832 /* This is a reloc against a global symbol. We
2833 have not yet output all the local symbols, so
2834 we do not know the symbol index of any global
2835 symbol. We set the rel_hash entry for this
2836 reloc to point to the global hash table entry
2837 for this symbol. The symbol index is then
2838 set at the end of elf_bfd_final_link. */
2839 indx = r_symndx - extsymoff;
2840 *rel_hash = elf_sym_hashes (input_bfd)[indx];
2842 /* Setting the index to -2 tells
2843 elf_link_output_extsym that this symbol is
2845 BFD_ASSERT ((*rel_hash)->indx < 0);
2846 (*rel_hash)->indx = -2;
2851 /* This is a reloc against a local symbol. */
2854 isym = finfo->internal_syms + r_symndx;
2855 sec = finfo->sections[r_symndx];
2856 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2858 /* I suppose the backend ought to fill in the
2859 section of any STT_SECTION symbol against a
2860 processor specific section. */
2861 if (sec != NULL && bfd_is_abs_section (sec))
2863 else if (sec == NULL || sec->owner == NULL)
2865 bfd_set_error (bfd_error_bad_value);
2870 r_symndx = sec->output_section->target_index;
2871 BFD_ASSERT (r_symndx != 0);
2876 if (finfo->indices[r_symndx] == -1)
2882 if (finfo->info->strip == strip_all)
2884 /* You can't do ld -r -s. */
2885 bfd_set_error (bfd_error_invalid_operation);
2889 /* This symbol was skipped earlier, but
2890 since it is needed by a reloc, we
2891 must output it now. */
2892 link = symtab_hdr->sh_link;
2893 name = bfd_elf_string_from_elf_section (input_bfd,
2899 osec = sec->output_section;
2901 _bfd_elf_section_from_bfd_section (output_bfd,
2903 if (isym->st_shndx == (unsigned short) -1)
2906 isym->st_value += sec->output_offset;
2907 if (! finfo->info->relocateable)
2908 isym->st_value += osec->vma;
2910 finfo->indices[r_symndx] = output_bfd->symcount;
2912 if (! elf_link_output_sym (finfo, name, isym, sec))
2916 r_symndx = finfo->indices[r_symndx];
2919 irela->r_info = ELF_R_INFO (r_symndx,
2920 ELF_R_TYPE (irela->r_info));
2923 /* Swap out the relocs. */
2924 input_rel_hdr = &elf_section_data (o)->rel_hdr;
2925 output_rel_hdr = &elf_section_data (o->output_section)->rel_hdr;
2926 BFD_ASSERT (output_rel_hdr->sh_entsize
2927 == input_rel_hdr->sh_entsize);
2928 irela = internal_relocs;
2929 irelaend = irela + o->reloc_count;
2930 if (input_rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2932 Elf_External_Rel *erel;
2934 erel = ((Elf_External_Rel *) output_rel_hdr->contents
2935 + o->output_section->reloc_count);
2936 for (; irela < irelaend; irela++, erel++)
2938 Elf_Internal_Rel irel;
2940 irel.r_offset = irela->r_offset;
2941 irel.r_info = irela->r_info;
2942 BFD_ASSERT (irela->r_addend == 0);
2943 elf_swap_reloc_out (output_bfd, &irel, erel);
2948 Elf_External_Rela *erela;
2950 BFD_ASSERT (input_rel_hdr->sh_entsize
2951 == sizeof (Elf_External_Rela));
2952 erela = ((Elf_External_Rela *) output_rel_hdr->contents
2953 + o->output_section->reloc_count);
2954 for (; irela < irelaend; irela++, erela++)
2955 elf_swap_reloca_out (output_bfd, irela, erela);
2958 o->output_section->reloc_count += o->reloc_count;
2962 /* Write out the modified section contents. */
2963 if (! bfd_set_section_contents (output_bfd, o->output_section,
2964 finfo->contents, o->output_offset,
2965 (o->_cooked_size != 0
2974 /* Generate a reloc when linking an ELF file. This is a reloc
2975 requested by the linker, and does come from any input file. This
2976 is used to build constructor and destructor tables when linking
2980 elf_reloc_link_order (output_bfd, info, output_section, link_order)
2982 struct bfd_link_info *info;
2983 asection *output_section;
2984 struct bfd_link_order *link_order;
2986 reloc_howto_type *howto;
2989 struct elf_link_hash_entry **rel_hash_ptr;
2990 Elf_Internal_Shdr *rel_hdr;
2992 howto = bfd_reloc_type_lookup (output_bfd, link_order->u.reloc.p->reloc);
2995 bfd_set_error (bfd_error_bad_value);
2999 /* If this is an inplace reloc, we must write the addend into the
3001 if (howto->partial_inplace
3002 && link_order->u.reloc.p->addend != 0)
3005 bfd_reloc_status_type rstat;
3009 size = bfd_get_reloc_size (howto);
3010 buf = (bfd_byte *) bfd_zmalloc (size);
3011 if (buf == (bfd_byte *) NULL)
3013 rstat = _bfd_relocate_contents (howto, output_bfd,
3014 link_order->u.reloc.p->addend, buf);
3020 case bfd_reloc_outofrange:
3022 case bfd_reloc_overflow:
3023 if (! ((*info->callbacks->reloc_overflow)
3025 (link_order->type == bfd_section_reloc_link_order
3026 ? bfd_section_name (output_bfd,
3027 link_order->u.reloc.p->u.section)
3028 : link_order->u.reloc.p->u.name),
3029 howto->name, link_order->u.reloc.p->addend,
3030 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
3037 ok = bfd_set_section_contents (output_bfd, output_section, (PTR) buf,
3038 (file_ptr) link_order->offset, size);
3044 /* Figure out the symbol index. */
3045 rel_hash_ptr = (elf_section_data (output_section)->rel_hashes
3046 + output_section->reloc_count);
3047 if (link_order->type == bfd_section_reloc_link_order)
3049 indx = link_order->u.reloc.p->u.section->target_index;
3050 BFD_ASSERT (indx != 0);
3051 *rel_hash_ptr = NULL;
3055 struct elf_link_hash_entry *h;
3057 h = elf_link_hash_lookup (elf_hash_table (info),
3058 link_order->u.reloc.p->u.name,
3059 false, false, true);
3062 /* Setting the index to -2 tells elf_link_output_extsym that
3063 this symbol is used by a reloc. */
3070 if (! ((*info->callbacks->unattached_reloc)
3071 (info, link_order->u.reloc.p->u.name, (bfd *) NULL,
3072 (asection *) NULL, (bfd_vma) 0)))
3078 /* The address of a reloc is relative to the section in a
3079 relocateable file, and is a virtual address in an executable
3081 offset = link_order->offset;
3082 if (! info->relocateable)
3083 offset += output_section->vma;
3085 rel_hdr = &elf_section_data (output_section)->rel_hdr;
3087 if (rel_hdr->sh_type == SHT_REL)
3089 Elf_Internal_Rel irel;
3090 Elf_External_Rel *erel;
3092 irel.r_offset = offset;
3093 irel.r_info = ELF_R_INFO (indx, howto->type);
3094 erel = ((Elf_External_Rel *) rel_hdr->contents
3095 + output_section->reloc_count);
3096 elf_swap_reloc_out (output_bfd, &irel, erel);
3100 Elf_Internal_Rela irela;
3101 Elf_External_Rela *erela;
3103 irela.r_offset = offset;
3104 irela.r_info = ELF_R_INFO (indx, howto->type);
3105 irela.r_addend = link_order->u.reloc.p->addend;
3106 erela = ((Elf_External_Rela *) rel_hdr->contents
3107 + output_section->reloc_count);
3108 elf_swap_reloca_out (output_bfd, &irela, erela);
3111 ++output_section->reloc_count;